Prof. Nicholson on Classification of " Tahnlate Corals!' 91 



Journ. Sci. and Arts, ser. 2, vol. xxvi., p. 140, 1858, and Proc. 

 Bost. Soc. Nat. Hist., vol. vi., p. 373, 1859). This conclusion 

 has since been fully confirmed by the researches of Moseley, 

 as I shall subsequently show, but it by no means affords a 

 sufficient basis for the generalisation put forth by Agassiz — 

 namely, that in view of the hydrozoal nature of Millepora, 

 all the "Tabulate" corals (as well as the Bugosa) should be 

 removed from the Actinozoa to the Hydrozoa. 



Another very important discovery was made at a later date 

 by Professor Verrill, who showed, from an examination of 

 the living animal, that the genus Pocillopora, Lam., is truly a 

 Zoantharian, and referable to the large and widely-distributed 

 group of the Aporose corals, in the neighbourhood of the 

 family Oculinidce (Trans. Conn. Acad., vol. i., pp. 2, 523, 1870). 

 Moreover, in another important memoir, we find the same 

 high authority strongly urging the identity of a great many 

 of the " Tabulate Corals " with the ordinar}^ Zoantharia, and, 

 in particular, maintaining the view that the great group of 

 the Favositidm is truly referable to the Porosa, and probably 

 to be actually placed in the existing family of the Poritidce 

 (Amer. Journ. Sci. and Arts, ser. 3, vol. iii., p. 187, 1872). 



In the year 1872 was also published the well-known 

 " Third Pteport on the British Corals," by Professor Martin 

 Duncan (Ptep. Brit. Ass., 1872). In this important memoir. 

 Professor Duncan deals very largely with the structure and 

 affinities of the "Tabulate Corals," his wide knowledge of 

 both living and extinct Actinozoa rendering his views upon 

 this subject peculiarly valuable and suggestive. Dr Duncan 

 retains the " Tabulata " of Edwards and Haime as a great 

 sub-division of the Zoantharia, and his principal conclusions 

 will be readily seen by a glance at the following table of the 

 families and genera of the " Tabulata " as adopted by him : 



Families. 



„-.,- , \ Milleporidce. Coenenchyma cellular. 



With ccenenchyma. | ^,^,^,,^,v^,,, Ccenenchyma compact. 



^^^.,, , C Favositidce. Walls perforated. 



Without coenen- J j^^iy^i^^i^^ WaUs imperforate, 

 chyma. \^Alwolitidai. Septa tridentate. 



